1. Technical Field
The present disclosure relates to methods for making sulfur based composites. The present disclosure particularly relates to a method for making sulfur-graphene composites.
2. Description of Related Art
The goal of lithium ion battery development is high energy density, safety, and sustainability. This is typically determined by the current progress of available materials. Currently, elemental sulfur has the highest theoretical capacity and theoretical specific energy density of all known cathode materials for rechargeable lithium ion batteries. Combined with abundant resources and low cost, sulfur shows great potential as the cathode for the next generation of high performance lithium batteries.
However, previous studies of Li—S batteries with organic electrolytes revealed problems including low cycling stability and poor cycle life, because of the insulating nature of sulfur and the volume change during cycling of the cell. Composite conducting agents, such as porous carbon, carbon nanotubes, and graphene with sulfur have been attempted to improve the conductivity of the cathode material. To composite the conducting agents with sulfur, elemental sulfur is sublimed at a high temperature to produce sulfur vapor, and then the sulfur vapor is deposited on a surface of the conducting agents. However, it is difficult to control the morphology and particle size of the deposited sulfur, which results in an unsatisfactory cycling performance of the Li—S battery.
What is needed, therefore, is to provide a method for making sulfur-graphene composite material having relatively high cycling performance in a lithium ion battery.